100. WHAT ON EARTH ARE COSEC, SEC AND COT??? (A-level Maths, Pure Maths Video 100)

This is video 100 in my series of A-level Pure Mathematics videos. In this video, we define the following trigonometric functions:

(i) cosecant of x - referred to as cosec(x) = 1/sin(x)
(ii) secant of x - referred to as sec(x) = 1/cos(x)
(iii) cotangent of x - referred to as cot(x) = cos(x)/sin(x)

We also discuss briefly why cot(x) is not identical to 1/tan(x) for all values of x - since for odd multiples of pi/2 (i.e. pi/2, 3pi/2, 5pi/2, 7pi/2, etc) 1/tan(x) is undefined, but cot(x) is defined to be 0. But otherwise, we can say that 1/tan(x) is the same as cot(x) for all over values.

Видео 100. WHAT ON EARTH ARE COSEC, SEC AND COT??? (A-level Maths, Pure Maths Video 100) канала A-Level Maths Tutor UK